1. Field of the Invention
The present invention pertains to the field of integrated circuit memory devices. More particularly, this invention relates to block status registers in a memory device that provide user accessible block specific status information.
2. Art Background
A flash memory device contains a flash cell array for nonvolatile random access data storage in a computer system. A typical flash cell array may be subdivided into a set of flash array blocks. Prior flash memory devices usually implement a write control circuit for programming and erasing areas of the flash cell array. The write control circuit programs and erases the flash cells by applying a predetermined sequence of program level voltages to the flash cells.
Prior flash memory devices typically provide status information to the user through a status register. The write control circuit in such prior flash memory devices usually sets and clears status bits in the status register during program or erase operations. A driver program provided by the user reads the status register during data transfer sequences to the flash memory device. The driver program uses the status bits to determine proper synchronization and control of the data transfer. The status bits commonly include status bits indicating whether the flash memory device is either busy or ready to accept commands or data, and status bits indicating whether a program or erase operation has failed, as well as status bits indicating other status and error information.
Unfortunately, such prior flash memory devices only provide global status information to the user. The status information in such devices is global because the status bits indicate the status of the entire flash memory device even when the device is subdivided into multiple flash array blocks. As a consequence, the driver program must incur the overhead required to maintain a correlation between the global status information from the status register and the block specific operations on the flash array blocks. Such extra overhead greatly increase the cost and complexity of the driver program and can significantly decrease write transaction throughput to the flash memory devices.